Getting error : code is 400002 and error message is Signature is not valid for this request while doing create order API (POST /binancepay/openapi/v3/order) of binance pay

API Futures API
1

Hello everyone,
I want to integrate Binance Pay into my app, and I’m using this document for reference.
And I am using Postman to test the API, but it is giving the error “The signature is not valid for this request.”

But I have followed everything mentioned in the docs
Here is my code example as I wrote it in Postman:

Body (as a raw) :

{
    "env": {
        "terminalType": "WEB"
    },
    "merchantTradeNo": "98253829372",
    "orderAmount": 1,
    "currency": "USDT",
    "description": "very good Ice Cream",
    "goodsDetails": [
        {
            "goodsType": "01",
            "goodsCategory": "D000",
            "referenceGoodsId": "7876763A3B2312",
            "goodsName": "Ice Cream"
        }
    ]
}

Headers that I am passing, and some headers are auto generated by postman :

img1
img11801×622 46.6 KB

and for this I am using postman script (pre-request)
Note this code contain 2 body variable I have tried with both of them

const crypto = require('crypto-js')
const secretKeyValue = 'my_secrate_key provide by Binance pay'
pm.environment.set("secret_key", secretKeyValue);

const body = "env[terminalType]=WEB&merchantTradeNo=98253829372&orderAmount=1&currency=USDT&description=very%20good%20Ice%20Cream&goodsDetails[0][goodsType]=01&goodsDetails[0][goodsCategory]=D000&goodsDetails[0][referenceGoodsId]=7876763A3B2312&goodsDetails[0][goodsName]=Ice%20Cream"

// const body = {
//     "env": {
//         "terminalType": "WEB"
//     },
//     "merchantTradeNo": "98253829372",
//     "orderAmount": 1,
//     "currency": "USDT",
//     "description": "very good Ice Cream",
//     "goodsDetails": [
//         {
//             "goodsType": "01",
//             "goodsCategory": "D000",
//             "referenceGoodsId": "7876763A3B2312",
//             "goodsName": "Ice Cream"
//         }
//     ]
// }

function generateRandomString() {
    let randomString = '';
    for (let i = 0; i < 32; i++) {
        const randomCharCode = Math.floor(Math.random() * 52);
        const charCode = randomCharCode < 26 ? randomCharCode + 65 : randomCharCode + 71;
        randomString += String.fromCharCode(charCode);
    }
    return randomString;
}

function createSignature(timestamp, nonce, body, secretKey) {
  const payload = `${timestamp}\n${nonce}\n${body}\n`;
  const hmac = crypto.HmacSHA512(payload, secretKey);
  const signature = hmac.toString(crypto.enc.Hex).toUpperCase();
  return signature;
}

function generateRandomString(length) {
    const charset = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
    const randomBytes = crypto.lib.WordArray.random(length);
    let result = "";
    for (let i = 0; i < length; i++) {
        const byte = randomBytes.words[i] & 0xFF;
        const index = byte % charset.length;
        result += charset[index];
    }
    return result;
}

const randomNonce = generateRandomString(32)
pm.globals.set("random-nonce", randomNonce);

const unixTimestamp = new Date().getTime()
pm.globals.set("unixTimestamp", unixTimestamp);


const secretKey = pm.environment.get("secret_key");
console.log(secretKey)
const hashValue = createSignature(unixTimestamp, randomNonce, body, secretKey)
// // console.log(hashValue)
pm.globals.set("paysignature", hashValue);

Can anyone please help me to find a solution for this error.
Thanks

2

Hey,
Have you checked this repository: binance-pay-signature-examples/nodejs/merchant.js at master · binance/binance-pay-signature-examples · GitHub
It provides a helpful example on how to create a signature for Binance Pay endpoints.
Hope that it will help you.

3

Thanks Albin,
By following this document, I can now create an order response